Doupo: Life Simulator System - Chapter 634: Choose One Out of Three

The male student, Fukai Nagamasa, ignores his studies for college entrance exams in favor of following the path to chuunibyou. As he fainted during night cramming session before the exams, he realized that he was transported to a parallel world as a feudal lord in the Sengoku Era. Not to mention that suddenly, he was marrying the sixth Demon King, Oda Nobunaga’s little sister, the one who was purported to be an unrivaled beauty?

The sky was painted gray forever. The light of the sun was restrained. The darkness of the night was deeper than ever. At such a time, he belonged to a class people didn’t even recognize as ’human’. He was at the bottom of the social stratum, a slave. And when his only family was taken away from him... he no longer had a purpose in life. Yet, he clung to life because of his promise. And he set an impossible goal for himself, just so he’d have an excuse to live. When he finally reached a place he never expected to be, in pursuit of a purpose he expected to fail and die miserably trying to fulfill... he awoke to a night that would change his entire life. He was an insignificant fly, a mere speck in the destruction of the Empire. But he... survived. And, despite being a slave, he gained the blessing of a king. Or rather, the curse...

Calling the old god’s mage, the knight who inherits the bloodline, looking forward to the glory of yesterday;

The noise of steam engines and the roar of cannons indicate the direction of the future;

An Sen, who was living in this world, embarked on a road that had never been imagined;

In the ashes of the old world…he shall be crowned king!

- Description from novelbuddy

The MC entered the body of the An family eldest son, An Ziran, an arrogant 16 years old boy who weighed 78 kg (~171-172 lbs), who only knew how to eat, play and sleep. Seeing his current body, An Ziran decided his first priority was to LOSE WEIGHT!